Fix hci support on linux kernel 6.9+

Prior to this fix, The stateChanged powered_on event will not arrive for bleno with an error called from setFilter (EINVAL, Invalid argument). The buffer for the socket filter was 14 bytes and is a constant value of the same length. However, AF_BLUETOOTH setsockopt kernel handler validates the len of the struct hci_filter and expects it to be bit aligned, zero padding (16 bytes), see abandonware/node-bluetooth-hci-socket#60 (comment) for more detail
Additionally, change hardcoded literal '2902' in gatt peripheral initialisation for notify to use a constant string rather than string literal.

lib/hci-socket/gatt.js

@@ -39,6 +39,7 @@ const GATT_INCLUDE_UUID               = 0x2802;
 const GATT_CHARAC_UUID                = 0x2803;
 
 const GATT_CLIENT_CHARAC_CFG_UUID     = 0x2902;
+const GATT_CLIENT_CHARAC_CFG_UUID_S   = '2902'
 const GATT_SERVER_CHARAC_CFG_UUID     = 0x2903;
 
 const ATT_ECODE_SUCCESS               = 0x00;
@@ -208,7 +209,7 @@ class Gatt  extends EventEmitter {
           this._handles[clientCharacteristicConfigurationDescriptorHandle] = {
             type: 'descriptor',
             handle: clientCharacteristicConfigurationDescriptorHandle,
-            uuid: '2902',
+            uuid: GATT_CLIENT_CHARAC_CFG_UUID_S,
             attribute: characteristic,
             properties: (0x02 | 0x04 | 0x08), // read/write
             secure: (secure & 0x10) ? (0x02 | 0x04 | 0x08) : 0,
@@ -218,6 +219,15 @@ class Gatt  extends EventEmitter {
 
         for (let k = 0; k < characteristic.descriptors.length; k++) {
           const descriptor = characteristic.descriptors[k];
+
+          //https://github.com/abandonware/bleno/issues/51
+          //above, if the characteristic defines notify, the 2902 characteristic descriptor is added automatically
+          //if the peripheral also declares this, we don't want to add it again
+          //flags (properties, secure etc) above are better defined
+          if(descriptor.uuid == GATT_CLIENT_CHARAC_CFG_UUID_S)
+          {
+            continue;
+          }
 
           handle++;
           const descriptorHandle = handle;

lib/hci-socket/hci.js

@@ -147,7 +147,7 @@ class Hci extends EventEmitter {
   }
 
   setSocketFilter() {
-    const filter = Buffer.alloc(14);
+    const filter = Buffer.alloc(16);
     const typeMask = (1 << HCI_EVENT_PKT) | (1 << HCI_ACLDATA_PKT);
     const eventMask1 = (1 << EVT_DISCONN_COMPLETE) | (1 << EVT_ENCRYPT_CHANGE) | (1 << EVT_CMD_COMPLETE) | (1 << EVT_CMD_STATUS) | (1 << EVT_NUMBER_OF_COMPLETED_PACKETS);
     const eventMask2 = (1 << (EVT_LE_META_EVENT - 32));